Diseases Which Challenge Global Wheat Production: Root, Crown, and Culm Rots

Most wheat ('Triticum' spp.) diseases caused by root-, crown- and lower culm-infecting fungi are not yet effectively managed by genetic resistance or by application of a fungicide or biological control agent. The best management strategy for many of these diseases continues to depend upon changing the soil environment in ways that either influence the survival of the pathogen between susceptible host crops or the pathogen's virulence during the infective stage (Cook and Veseth 1991). The soilborne plant-pathogenic fungi that cause the seven root, crown, and culm rots summarized in this chapter are heavily influenced by soil physical and chemical properties, by interactions with associated microbes and microfauna in soil and on plant surfaces, and by the capacity of plants to serve as hosts for growth and multiplication. The complexity of factors affecting these pathogens before and during pathogenesis is immense.